Growing Winter Tomatoes in a Greenhouse

Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request:  I've just set up a small garden greenhouse. It has a heater, warming mats, fans, etc. I'm thinking about growing tomatoes during the winter. Would you please provide some advice on such a venture?

Help Desk Response:  Thank you for your email to the UC Master Gardener Program Help Desk about growing tomatoes in the winter in a (warm) greenhouse. 
 

This is a great project… something I've considered at times with my greenhouse, but have yet to try. Tomatoes are really a (tender) tropical perennial that can survive and produce for several years given the appropriate growing conditions, primarily eliminating cold conditions along with proper lighting. Other members of the Solanaceae family besides tomatoes (e.g., egg plants, peppers) can also be “overwintered” with proper protection and appropriate growing conditions. On the garden radio programs I listen to, overwintering peppers in pots in greenhouses to get a fast start on their second year of growth is apparently a current favorite.

It appears that University of California does not have significant information on growing tomatoes in a greenhouse for the home gardener. However, I've listed below a few links to reputable articles from other sources that may be helpful in setting up and growing tomatoes in a greenhouse at home.

• This website from the University of Oregon, Department of Horticulture, has information on fertilization, soil, temperature and light, which may be helpful. Though the information is for commercial growing operations, some of it is applicable to home greenhouses. http://horticulture.oregonstate.edu/content/tomato-greenhouse
  
  
• This link to SF Gate discusses good tomato varieties for greenhouse growing conditions and also, mentions ways to support the growing plants. https://homeguides.sfgate.com/types-tomatoes-greenhouse-production-30810.html
  
  
•  This Wikihow website has some helpful information on various aspects of growing tomato plants in greenhouses.  https://www.wikihow.com/Grow-Tomatoes-in-a-Greenhouse

There are also many other web sites and YouTube videos available on the subject, but I would use them cautiously, and cross-check other references if they seem “too good to be true”.

Please contact us again if you have further questions. Good luck with your winter tomatoes.

Help Desk of the UC Master Gardener Program of Contra Costa County (SMT)

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Note:  UC Master Gardeners Program of Contra Costa's Help Desk is available almost year-round to answer your gardening questions.  Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (//ucanr.edu/blogs/CCMGBlog/)